> PEP 658 went live on PyPI in May 2023. uv launched in February 2024. The timing isn’t coincidental. uv could be fast because the ecosystem finally had the infrastructure to support it. A tool like uv couldn’t have shipped in 2020. The standards weren’t there yet.

How/why did the package maintainers start using all these improvements? Some of them sound like a bunch of work, and getting a package ecosystem to move is hard. Was there motivation to speed up installs across the ecosystem? If setup.py was working okay for folks, what incentivized them to start using pyproject.toml?

> If setup.py was working okay for folks, what incentivized them to start using pyproject.toml?

It wasn't working okay for many people, and many others haven't started using pyproject.toml.

For what I consider the most egregious example: Requests is one of the most popular libraries, under the PSF's official umbrella, which uses only Python code and thus doesn't even need to be "built" in a meaningful sense. It has a pyproject.toml file as of the last release. But that file isn't specifying the build setup following PEP 517/518/621 standards. That's supposed to appear in the next minor release, but they've only done patch releases this year and the relevant code is not at the head of the repo, even though it already caused problems for them this year. It's been more than a year and a half since the last minor release.

Because static declaration was clearly safer and more performant? My question is why pip isn't fully taking advantage